Fossil fuels are society's major energy sources and the primary raw materials for the chemicals industry. However, there are significant concerns associated with their sustainability, depletion and cost. In particular, many of the UK's North Sea reserves will soon become uneconomic / depleted, so we need to find alternatives urgently. Furthermore, the combustion of fossil fuels, e.g. during energy conversion, releases carbon dioxide and other greenhouse gases that contribute to global warming. The UK is already committed to an 80% reduction in greenhouse gas emissions by 2050, but significantly greater reductions (85%) are likely to be necessary in order to prevent devastating climate change (>2 degree C increase in temperature). Energy conversion for electricity and transport is responsible for 74% of CO2 emissions; new sustainable energy sources are essential. These new energy sources must be CO2 neutral or, even better, CO2 depleting. One solution is to use carbon dioxide itself as the fuel and feedstock material. Our solution is to react CO2 with H2 or water, using chemical, photochemical or electrochemical catalysts, to produce liquid transport fuels, such as methanol. Flue gases from power stations and/or industrial process, such as metal/alloy manufacture, are major contributors to UK CO2 emissions and will be abundant sources of CO2 for the foreseeable future. Many other industrial emissions also contain considerable concentrations of CO2 including those derived from biological processes, e.g. fermentation. The hydrogen required will be produced by water electrolysis powered by solar or other renewable source of energy. The key economic issue lies in decreasing the energy required for the processes. We aim to achieve this via the development of new, highly active metal/metal oxide nano-structured catalysts, which offer superior performance due to their high surface areas, reduced loadings, low overpotentials and which can be synthesised controllably. We shall use three parallel, yet complementary, approaches to energise the process: direct chemical (thermal) hydrogenation, electrochemical and photochemical reductions of carbon dioxide and water.Our team comprises scientist, engineers and environmental policy researchers at Imperial College London and University College London. We have expertise in chemical catalysis, electrochemistry, photochemistry, reactor engineering, materials science, nanotechnology, sustainable chemistry and environmental science. We have a significant track record in the activation and use of carbon dioxide as a resource. The project will also involve collaborations with, and be support by, the Imperial College London Centre for Carbon Capture and Storage (CCS), the Energy Futures Lab and the Grantham Institute for Climate Change.

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High surface area nanoporous films formed by sintering metal oxide nanoparticles are highly stable, non-toxic and inexpensive to produce on an industrial scale. They find a wide range of applications in gas sensing and catalysis where high surface area is essential to maximise the interaction of molecules with the film. They also find applications as charge transport layers in third generation solar cells, e.g. dye- or perovskite-sensitised cells, where efficient photoinjection of electrons and holes is ensured by coating nanoporous films with a light absorbing material. For solar cells, as well as for other important applications of nanoporous films such as electrodes in fuel cells and photoelectrochemical cells, good charge carrier mobility is also an essential requirement. Unfortunately, despite their numerous advantages, the electronic mobility of nanoporous oxide films is in general very poor. For example, the mobilities of nanoporous TiO2, ZnO and SnO2 films have been shown to be between two and four orders of magnitude smaller than those of corresponding single crystals. This low mobility is a key factor limiting the efficiency of (photo-)electrochemical and photovoltaic applications and is usually attributed to increased charge carrier trapping at surfaces and at interfaces between nanoparticles. Since charge trapping is associated with ions near surfaces we hypothesise that it should be possible to eliminate these traps by suitable chemical modification of the surfaces of nanoparticles prior to sintering into a film. This approach would retain the advantages of nanoporous films in terms of high surface area, non-toxicity and processability while improving mobility. Such modifications have been attempted previously, but due to the lack of understanding on the origin of charge trapping or the effects of surface modification, success has been limited. Here, we propose to combine the predictive power of first principles theoretical modelling with structural, spectroscopic and photophysical materials characterisation, in order to quantify the factors responsible for charge trapping at surface and interfaces in nanoporous oxide films at an atomistic level. Once validated and refined on unmodified films, theoretical methods will be used to assess modification strategies to reduce charge-trapping. In particular, we will consider the incorporation/substitution of anions and cations near the surface of oxide nanoparticles to eliminate the problematic trapping sites. The ability to theoretically screen various possible modification routes (i.e. different cations and anions) is a key advantage of our proposed approach. Application, testing and optimisation of such strategies may offer a new paradigm for knowledge-led design of solar oxide materials. We aim to demonstrate the effectiveness of our approach by increasing the mobility of nanostructured TiO2 and ZrO2 to deliver an improvement in the efficiency of perovskite-sensitised solar cells, which are emerging as an attractive third generation photovoltaic technology. The size of the third generation photovoltaic market is predicted to grow to $38bn by 2022, making this an area with significant potential for economic impact. Improving the mobility of nanoporous oxides could bring the efficiency of these devices from their current level (about 20%) to closer to the theoretical maximum of about 30%. An increase in overall efficiency from 20% to only 23% percent would increase the total power output by 15%, which when coupled with lower manufacturing costs would make the technology very attractive. We will work with leading manufacturers of nano-TiO2 (Cristal) and perovskite-sensitised solar cells (Dyesol Limited) to test the performance of our modified films. More generally, the ability to tailor the electronic properties of interfaces in nanoporous films by controlled modification should find applications in other technologies including sensing, catalysis and electronics.

The fossil fuel reserves of the world are rapidly diminishing and are also the prime cause for global warming. Solar energy represents a major, largely untapped energy source which could easily satisfy current and future global energy demands. Any solar energy conversion device must be inexpensive per m2, efficient and long-lasting. In this programme, novel, inorganic water-splitting systems, called macro-photocatalytic diode cells, MPCDs, utilising a range of new and established visible-light absorbing photocatalyst materials, will be developed for splitting water using sunlight in separate compartments. The latter feature is important as it will minimise, if not eliminate, the various efficiency-lowering recombination reactions associated with mixed product generation. The work programme involves a number of novel aspects including: the preparation of new nanoparticulate, crystalline photocatalyst materials, fabricating them into different novel photodiode formats and the synthesis and utilisation of new redox catalysts. The use of nanoparticulate semiconductor photocatalysts, made via continuous hydrothermal flow synthesis, CHFS, in conjunction with gel casting for robust porous supports, is a particularly important and novel advance, as too is the proposed combinatorial approach to the preparation of photocatalyst films by CVD. The project will develop a significant amount of the underpinning science required for the fabrication of the final, optimised, efficient MPCDs and include a study of the underlying reaction mechanisms, using time-resolved transient absorption spectroscopy. The proposal offers a route to achieving a step change in efficiency for energy capture from the sun and aims to deliver efficient, scalable demonstrators of the MPCD technology, suitable for development into pilot plant systems in the second phase of funding.

Atomistic structural, electronic and chemical models are the basis of modern material science, with data acquired under regular high vacuum conditions by analysis of mainly static specimens. However, the properties and hence functionality of many materials crucially depend on the environmental conditions to which they are exposed. Accordingly, relevant analyses of structure, composition and properties need to be conducted under controlled continuous dynamic conditions and the vision of this project is to enable and fully integrate the capabilities needed to accomplish these goals to understand nanomaterial-environment interactions, and ultimately to create nanomaterials by design. The overarching vision of this proposal is to fill the need for the fully integrated nanomaterials analysis with single atom sensitivity under dynamic process conditions in environmental conditions. The aim is to provide the state of the art tool available to UK research community to address the outstanding materials problems that underpin a number of EPSRC research themes from manufacturing the future to health and environment. Fully in situ and operando operations are needed to ensure the integrity of sample data. In practice this extends from sample synthesis or activation, through the ensuing operations, reactions or other processes or tests. Hence, resources are sought to establish a state-of-the-art, aberration corrected STEM instrument (200 to 40 kV) with 0.08 nm image resolution and comprehensive analytical functions for chemical and electronic state analysis with electron energy loss spectroscopy (EELS), related imaging filter (GIF), direct electron detection, and elemental analysis with a transformational high sensitivity (and acceptance angle) silicon drift detection (SDD) energy dispersive x-ray (EDX) spectrometer. The new instrument will be modified at York to include added unique functionalities, along the lines of the research led by the group. Methods and some hardware will be transferred from the original proof-of-concept and aged (2005) first generation instrument at York. The advantages of the open aperture 'gas-in-microscope' concept promoted at York are expected to be especially significant at the lower accelerating voltages of 80 and 40 kV to be available to reduce damage due to specimen-electron beam interactions. The new instrument and attendant expertise will be organised, actively promoted, operated and managed as a new national capability with connections to the national SuperSTEM and ePSIC laboratories, including CI representation from both organisations, for advice and user guidance and active assistance external promotion and strategic as well as tactical management. Wide networking will add to the framework for organising the new capability but will not exclude more ad hoc bilateral interactions; in part to promote the core science needed at the heart of such an 'organisation'. The scientific benefits of the proposed centre for excellence in environmental aberration corrected STEM will greatly contribute to the current research initiatives in the UK related to nanomaterials for energy applications, information technologies/internet of things, and catalysis. The key contribution will be in fundamental understanding of the nanomaterials environment interactions enables trough atomistic imaging and analysis of the dynamic processes that take place either during material fabrication or in action. The project will make a significant contribution to what the future of the UK and of the world will look like; through better understanding of societal, scientific, economic, and environmental challenges and opportunities.